In Israel, schools are protected by armed guards, and everyone is on some sort of an alert for suspicious objects or people.

Cars and personal belongings are checked at cafés, movies theaters, public buildings and malls.

Although security guards here are not your typical ex-Navy SEALS, they do act as a first barrier – a line of defense that could have saved the lives of the innocent children at Sandy Hook Elementary School.

Young men carrying M16 rifles – soldiers either on their way back or coming home from their military base – are a common sight on main streets in Jerusalem or Tel Aviv.

However, it is very difficult for any Israeli civilian to purchase and own a gun, and all must have a license to do so. The ownership of assault rifles by a private person is forbidden, and pistols are limited to one per person.

In a country with a population of almost 8 million there are only about 300,000 weapons, of which just over half - 170,000 - belong to private individuals. The rest belong to security institutions.

The license process, which must be completed every year, includes mental and physical health checkups as well as a firing-range exercise. Most importantly, it is a crime with harsh penalty to carry a weapon in Israel without a license.

Security guards must meet regulations before they are granted the license to carry a gun; they must be at least 27 years old, unless they served in the army, in which case they can apply at the age of 21. They also need to be a resident of Israel for at least three years and sign a waiver that gives the health ministry and the police the right to check their health and criminal records.

Yariv, owner of the Lahav weapon shop in Tel Aviv, told Israeli Army radio: "A very little amount of people buy private guns, since the Israeli citizen knows in advance that his chances to buy and own a gun amounts to zero.

“Most of the buyers are men who are demanded by their work to carry a weapon.”

There are only a few tens of thousands of legal guns in Israel, most owned by settlers living in the West Bank who are granted dispensation because of the need for self-defense while traveling to and from the West Bank.

Such measures mean that, despite a backdrop of violence committed with illegal weapons, there are hardly any random killings at all. It is impossible for a 20-year-old to buy and own a gun openly.